This report describes the Educational Testing Service professional development/assessment system for student and beginning teachers, "Pathwise," a classroom observation instrument, as used in the California Beginning Teacher Support and Assessment Program (BTSA) for teacher education. Three themes were noted by "Pathwise" users in the California program: (1) "Pathwise" gave all program participants a common language for discussion of teaching and learning; (2) training in understanding and recognizing criteria was an extremely valuable professional development experience; and (3) beginning teachers reported they were functioning as more experienced teachers than if they had not participated in the program. "Pathwise" supports the idea that professional development should be guided by linking teaching performance with research on teaching. It is grounded in 19 essential teaching criteria that are divided into 4 domains: organizing content knowledge for student teaching; creating an environment for student learning; teaching for student learning; and teacher professionalism. It models an active, constructivist view of learning and teaching in which life experiences and prior knowledge are important instructional resources, and it includes a multicultural perspective. It is based on the premise that teachers need to be provided with supportive feedback, generated from observation of performance based on the 19 criteria. "Pathwise" is currently in use in California and Minnesota in 18 local school districts; a number of colleges in California, Delaware, Minnesota, and Ohio also use the program. It is offered through institute training sessions nationwide and is available in 2- or 5-day sessions. (NAV)